Integrase inhibitors affect the way HIV works in the body. To get a better understanding, let’s explore HIV infection from the beginning.

HIV is transmitted between people through the exchange of bodily fluids, such as blood, semen, rectal and vaginal fluids, and breast milk. It’s not transmitted through saliva.

Once the virus is in the body, HIV attacks certain white blood cells, called CD4 cells, or T cells. These are the cells that tell the immune system to attack harmful organisms such as viruses and bacteria. HIV inserts itself into these T cells and takes control of them.

HIV does this by making an enzyme called integrase. Integrase allows the DNA of the virus to merge with the DNA of the T cells. Then, the HIV can control what the cells do. Without treatment, HIV can eventually take over too many T cells.

If this happens, the T cells can no longer signal the immune system to fight certain infections and other diseases, including cancers.

Integrase inhibitors rely on the fact that HIV needs integrase to replicate. These drugs stop HIV from being able to make integrase. Without the help of this enzyme, HIV can’t take over the T cells to copy itself.

With a combination of other HIV medications, integrase inhibitors can help keep HIV under control.

The U.S. Food and Drug Administration (FDA) approved the use of integrase inhibitors in 2007. The integrase inhibitors currently on the market include:

raltegravir (Isentress)

dolutegravir (Tivicay)

elvitegravir (available in combination with other drugs; no longer available alone)

bictegravir (available in combination with other drugs; not available alone)

Dolutegravir and elvitegravir are available in the following combination medications:

Integrase inhibitors are often used as the initial medications for treating HIV. Typically, they’re used with other drugs, often in one combination pill.

The other drugs in these combination pills help interfere with other ways that HIV works. The combined action of these drugs in this single-tablet regimen helps stop HIV through many different ways at once.

Integrase inhibitors have fewer side effects than other HIV drugs, because they work on the virus itself, not on the cells that HIV infects. The most common side effects with integrase inhibitors include:

diarrhea

nausea

fatigue

headache

insomnia

dizziness

Rarely, some people experience more serious side effects. These can include severe skin reactions and widespread inflammation.

If a person taking an integrase inhibitor starts to have uncomfortable side effects, they shouldn’t stop taking the drug without talking to their healthcare provider first.

Pausing or changing antiretroviral drugs can do more harm than good. The medications may become less effective, or the virus may become resistant to the drugs altogether. This means the drugs won’t work anymore to treat the virus.

People with HIV should consult their healthcare provider about other drug options before stopping or changing a drug regimen. The provider may be able to offer a different option.

During treatment for HIV, a healthcare provider will conduct blood tests from time to time, usually every three to six months.

Two specific measurements help them understand how the integrase inhibitors in the body are working to keep HIV infection under control. These measurements are viral load and T cell count.

Viral load

Viral load is the amount of HIV in a given sample of blood. A healthcare provider sends the blood sample to a lab, where they measure how many HIV copies are in 1 milliliter of the sample. The lower the viral load, the less HIV in the body.

An undetectable viral load is when the copies of HIV in the blood sample are fewer than the smallest amount the lab test can detect. An undetectable viral load doesn’t mean the virus is cured, though. HIV can still exist in bodily fluids, so a person with an undetectable viral load will still need to continue HIV treatment.

T cell count

A T cell count measures the number of T cells in the blood. It’s a general way to monitor the immune system. Generally speaking, the more T cells in the body, the more protection the body has against infections.

An important thing to remember is that the number of T cells in the body constantly changes. This is true for everyone, even people without HIV.

Having slightly lower levels of T cells on one test result doesn’t necessarily mean that HIV drugs aren’t working. Illness, vaccinations, fatigue, stress, and even the time of day can all affect T cell counts.

Integrase inhibitors need to stay at a consistent level in the body to be most effective. To help ensure the drug works at its best, people with HIV should:

Take the integrase inhibitor exactly as prescribed by their healthcare provider.

Get their healthcare provider’s approval before taking an integrase inhibitor with any other drug. Other medications may affect how HIV drugs work. These include prescription and over-the-counter drugs, such as calcium, aluminum magnesium antacids, and iron, as well as vitamins and supplements.

When taken as prescribed, integrase inhibitors may be able to provide effective, long-term management of HIV.